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cocoll and ammonium chloride. Precipitated carbonate of copper
is added to the hot liquid until no further effervescence occurs,
and some carbonate remains undissolved. It is filtered and
evaporated down on the \vater-bath until crystallisation sets in.
This is determined by removing and cooling a small portion in
a test-tube or watch-glass. The blue needles of copper glycocoll,
(CoH.jNO^Cu.H.jO, are tillered and washed, first with dilute and
then with stronger spirit. The mother liquor may be further eva-
porated, and. a. fresh quantity of crystals obtained. The copper
salt is dissolved in water and precipitated hot with hydrogen
sulphide, the free glycocoll passing- into solution. The pre-
cipitate is filtered and well washed, and the filtrate evaporated

to a small bulk on the water-hath. Crystals of glycocoll
separate out. Yield 15-20 grams. The loss is due to the
formation of di- and triglycolaminic acid, NH(CIL.COOH),,


+ NH4CI.

Fro forties. Large monoclinic crystals ; discoloured at 228 ;
m.p. 232-236 ; scarcely soluble in alcohol and ether, readily
soluble in water (r part glycocoll in 4 parts water).
Rcuction. \. Add a drop of copper sulphate to a solution of
g'lycocoll, and notice* the blue colour of the copper salt.
2. Add a drop of ferric chloride to the solution. It gives a
deep red colour. See Appendix^ p. 254.